1. Field of the Invention
The present invention relates to a drive device and an image pickup apparatus equipped with the drive device.
2. Description of the Related Art
Some image pickup apparatuses having an imaging element such as a CCD or the like are equipped with an image stabilizer unit which shifts the position of the imaging element in response to hand movement in order to correct the hand movement at the time of shooting. (See e.g. Japanese Patent Laid-Open No. 2006-259114.)
The image stabilizer unit operates as a drive device such that in general a piezoelectric actuator disposed on a lateral side portion generates a drive force to shift the imaging element in a plane vertical to an optical axis.
Specifically, the image stabilizer unit includes a piezoelectric actuator having a piezoelectric element expanding and contracting in response to applied electric voltage and a drive shaft extending from the piezoelectric element; a securing member provided with the piezoelectric actuator; and a displacement body (also called “the slider”) provided with an imaging element. In addition, the image stabilizer unit is configured to have a mechanism in which a bearing portion installed on the slider is friction-joined to a drive shaft of the piezoelectric actuator in the securing member. In the image stabilizer unit having such a mechanism, the slider is driven by use of the principle as below. If the drive shaft is displaced relatively moderately, the slider is displaced through the friction-joint force while simultaneously following the drive shaft. If the drive shaft is displaced relatively rapidly, the slider is not displaced because of slippage occurring at the friction-joint portion.